Process and apparatus for fractionated injections



Nov. 30, 1954 R. LETAC 2,695,611

PROCESS AND APPARATUS FOR FRACTIONATED INJECTIONS Filed oct. 18, 195o f/v' vf/vro E Pat?? fr/Qc BYMM Hrra en Em United States Patent PRCESS AND APPARATUS FOR FRACTIONATED INJECTIONS Roger Letac, Paris, France Application October 18, 1950, Serial No. 190,776 Claims priority, application France October 25, 1949 1 Claim. (Cl. 12S-173) The problem of injecting liquids in living organic tissues without the use of a needle has already been solved by using injectors `of the type which, since a long time, is used tor internal combustion engines. These njectors operate at -a high pressure and are provided with a calibrated port of a very small section. By placing the point of such an injector in immediate contact with the skin, the ejected liquid jet has the strength to permeate through the skin and to penetrate in the tissues.

Up to now, all the apparatuses designed for such purpose according to the above principle offer the same dr-awback, since a very small relative shifting of the injector from the place in contact of the skin may easily give rise to a traumatism and a laceration of the tissues and since it is practically impossible to prevent such shifting, particularly on account of the rellex movement of the skin.

The apparatus, object of the present invention, belongs to the above mentioned type, but is designed to cope with the serious drawback which has been pointed out. The device is characterized in that it includes means to carry on the injection in a fractionated manner.

A few embodiments are described hereafter, by way of example and are illustrated in the accompanying drawing in which:

Fig. 1 illustrates the machinery which will impart to the injectable liquid the brief impulses necessary to carry out the above stated inventive principle and feed an injector of a known type, working under an Iadjustable pressure.

The Figure 2 shows an auxiliary pump which can be substituted for the chief embodiment.

The first embodiment includes see Fig. l-an electric engine 1, controlled by a pedal 2, which through gears 3 and 4 drives a shaft 5 upon which is set a cam 6. The stem 7 of the piston 8 of the pump is held in contact with the cam by a drawback spring 9. On the pump barrel 10, which is screwed on the casing 10 of the eccentric, are mounted, on one side an elbow carrying the ask 11 supplying the injectable liquid and on the other side an air cock 12.

A exible piping 13 resisting to high pressures connects the pump with the injector, said injector having at its end 14 a calibrated port of very small size. A threaded knob 15 at the other end regulates the pressure of a spring 16 on the stem of the regulating valve 17.

The apparatus operates as follows:

The operator sets the supplying ask, lled with the liquid to be injected, and fills first the pump by working the air cock 12. He regulates the required injection pressure by adjusting adequately the knob 15 of the injector and brings the point of the injector in contact with the skin: when he presses on the pedal 21, the electric engine 1, driving, through gears 3, 4 and shaft 5, the cam 6, transmits to the piston 8 a reciprocating motion of a very small amplitude and high frequency. The liquid supplied by the ask 11 is conveyed by the flexible piping 13 in the injector wherefrom, at each impulse, it ows through the calibrated port under a pressure depending on the pressure of the spring 16 on the valve 17 and penetrates through the skin in the living tissues.

By operating in such a way, the injection is carried on 4in a fractionated manner, without any traumatism or laceration of the tissues.

The essential elements of the mechanism, specially the injector, the iexible piping and the pump barrel can easily be disconnected and subjected to sterilization.

The second embodiment-of 4the invention includes a pump shown on Fig. 2.

This subsidiary pump consists of a piston having two heads 18, equipped with a drawback spring 19 and sliding in a pump barrel 20. The liask containing the injectable liquid is fastened by a shoulder 21 on one end of the pump barrel 20. The piston rod 18 bears two crossheads: one of these 2 is driven by an auxiliary fluid, such as oil, brought under pressure by the main pump (see Fig. l), and the other cross-head 23 of Figure 2 transmits said pressure to the injectable liquid ilowing through a port 24. The subsidiary pump should be pl-aced as close as possible to the injector. The length of the circuit to be followed by the injectable liquid and the volume of the liquid in charge are reduced by using this subsidiary pump.

According to an alternative of this last embodiment, the flask containing the injectable liquid is designed to take the place of a subsidiary pump.

What l claim is:

An apparatus for injecting a given dose of a liquid product in living tissues, without the use of a hollow needle comprising a pressure responsive injector in combination with a power driven reciprocating pump device including a cylinder having an inlet port and a pressure port, a hollow bracket xed on said cylinder and registering with said inlet port, a vessel containing the liquid product disposed on said bracket and communicating therewith t'or supplying the cylinder with said liquid, a piston slidably disposed in said cylinder having a head portion and a tail portion, a spring urging said piston in a direction away from said inlet port, a casing having an 'aperture within which is engaged the tail portion of the piston, a shaft rotatably supported in said casing, a cam on said shaft and on which bears the tail portion of the piston, a switch controlled electrical motor drivingly connected to said shaft, screw means for removably xing the cylinder on said casing in registering position with the `aperture provided therein and a pipe connecting the pressure port of the cylinder to the injector.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,922,941 Francis et al. Aug. 15, 1933 2,322,244 Lockhart June 22, 1943 2,374,614 Nichols Apr. 24, 1945 2,406,207 Desault Aug. 20, 1946 2,421,475 Beeh June 3, 1947 2,527,615 Beale Oct. 31, 1950 OTHER REFERENCES A manuscript doctors thesis: Local Inltration of Tissues from a Machine Designed to Deliver High Pressure, High Velocity Jets of Fluid by John F. Roberts. The manuscript is in a bound volume in the Medical Library of Columbia University, College of Physicians & Surgeons, 630 W. 168th St., New York, Catalog number R747.C7/C73/ 1935. The volume is open to inspection by persons granted the privilege of use of the Library and is available on interlibrary loan. (A copy is in Div. 55 of the Pat. Off.) Figs. 1, 3, 5 and 7, and a description of Figs. 1, 3, 5 and 7. Pp. 13, 14, and 15 are cited. 

